Projection display apparatus

ABSTRACT

A projection display apparatus comprises luminous bodies, a luminous body driving portion which drives to turn on each of the luminous bodies, light leading members which optically separately lead and project light beams exiting from the luminous bodies, a movable portion which enables relative movement of the light leading members and the luminous bodies, and a light selection control portion which controls the movable portion and/or the luminous body driving portion in such a manner that light beams which enter the light leading members are selected. The apparatus further comprises a light modulation element which performs light modulation, an illumination member which illuminates the light modulation element with light beams from the light leading members, and a display control portion which controls the light selection control portion and the light modulation element in such a manner that the element suitable for light beams from the light leading members is illuminated.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/092,004, filed on Mar. 29, 2005, now U.S. Pat. No. 7,029,129 which isa continuation of PCT Application No. PCT/JP03/12027, filed on Sep. 19,2003, which was published under PCT Article 21(2) in Japanese, which isbased upon and claims the benefit of priority from Japanese patentapplication No. 2002-288936, filed on Oct. 1, 2002, which areincorporated by reference as if fully set forth.

FIELD OF INVENTION

The present invention relates to a projection display apparatus whichhas a high utilization efficiency of light and realizes high luminanceand reduction in size.

BACKGROUND

In examples of a condenser illumination apparatus which illuminates aspecified portion with high efficiency have heretofore been known suchas a car headlight, stand illumination, spot light, flashlight, andillumination unit for a data projector, light from a light emittingsource closer to a point source is reflected by a reflection unit whosereflection shape is devised, directivity of a light flux of thereflected light is enhanced by an optical lens, and the reflected lightis usually used to effectively perform condenser illumination.

In the same manner as in conventional illumination, even in thesecondenser illumination apparatus, there is much demand for obtaining abrighter illumination light without excessively enlarging a size of theapparatus. However, in order to obtain the brighter illumination light,although the size of the condenser illumination apparatus increase, anapplied power of the light emitting source is enlarged, thereby toincrease quantity of output light. Additionally, in order to enhance acondenser capability, the reflection unit or optical lens is appliedwhich is relatively enlarged with respect to the light emitting source.Therefore, to obtain brightness with good condenser efficiency, the sizeof the illumination apparatus has to be necessarily enlarged withrespect to the light emitting source. In other words, with a small-sizedlight emitting source which has a high output and which is close to thepoint source, it is also possible to miniaturize the whole illuminationapparatus. From this demand, the miniaturization of the light emittingsource of a conventional system has also been advanced, and particularlya small-sized light emitting source by a discharge type from which thehigh output is possible has been effective means at present.Additionally, even with the light emitting source of the small-sizeddischarge type, the driving by a high-voltage power source is requiredin which it is difficult to reduce a circuit scale. There are other manyproblems with respect to the miniaturization of the total illuminationapparatus. It is said that the miniaturization of the illuminationapparatus using the light emitting source of the small-sized dischargetype has already substantially approached limitation.

On the other hand, a light emitting diode (which will be referred to asa LED hereinafter) is remarkably noted as a next-generation small-sizedlight emitting source nowadays. The LED has heretofore had advantagessuch as small size, high durability, and long life, but has restrictionsof emission efficiency and emission output. Therefore, the LED has beenmainly used as indicator illumination for various instruments or aconfirmation lamp of a control stage because of restrictions of emissionefficiency and emission output. However, in recent years, the emissionefficiency has been rapidly improved, and it is said to be a matter oftime before the emission efficiency exceeds that of a high-pressuremercury lamp or fluorescent lamp of the discharge type assumed to haveheretofore had highest efficiency. By appearance of the high-efficiencyhigh-brightness LED, the high-output light emitting source by the LEDhas rapidly been brought into a practical use. In recent years, inaddition to red and green, a blue LED has entered a practical-use stage,and this also accelerates the application of the light emitting source.In actual, a plurality of high-efficiency high-brightness LED are usedto start the practical use in traffic lights, large-sized full-colordisplays for outdoors, various car lamps, and backlights of liquidcrystal displays in the cellular phones, which has heretofore beenimpossible in brightness or efficiency.

It is thought that this high-efficiency high-brightness LED is alsoapplied as a promising small-sized light emitting source of theillumination apparatus requiring a condensing property. The LED isoriginally superior to the other light emitting sources in life,durability, lighting-on speed, and simplicity of a lighting-on/drivingcircuit. Above all, the blue color is added, three primary colors areobtained as spontaneous-light emitting sources, and an application rangeof a full-color image display apparatus has therefore been enlarged.Typical examples of the illumination apparatus whose condensing propertyis demanded include a projector display apparatus in which a displayimage is formed and projected from image data. The projector displayapparatus has heretofore separated desired primary colors from awhite-based light emitting source by color filters, and has subjectedthe image data corresponding to each color to spatial light modulation.When the light obtained by the spatial light modulation is spatially ortemporally synthesized, color image display is possible. When thewhite-based light emitting source is used, only the desired color isseparated and used, therefore, the colors other than the separated colorare uselessly discarded by the filter in many cases. In this respect,since the LED emits the light of the desired color itself, a necessaryquantity of light can be emitted when necessary. As compared with theconventional white-based light emitting source, the light is not wasted,and the light of the light emitting source can be used with goodefficiency.

This superior application condition of the LED has been noticed, and,For example, Jpn. Pat. Appln. KOKAI Publication No. 11-32278, No.11-352589, and the like disclose an example in which the LED is appliedto the illumination apparatus for the projector display apparatus. Inthe technique disclosed in these publications, a plurality of LEDs isdisposed to secure a quantity of light. Some of fluxes from theindividual light emitting sources is condensed by optical elements suchas the optical lens, and the fluxes are controlled so that an imagedisplay element as a modulation device to be irradiated is well definedat an allowed incidence angle. For the image display elements such as aliquid crystal device broadly used in general, the allowed incidenceangle is small. Therefore, it is supposedly ideal to form the fluxhaving higher parallelism and to irradiate the elements. This is a veryimportant point in enhancing light use efficiency in the image displayelement.

BRIEF SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provideda projection display apparatus comprising:

a plurality of luminous bodies;

a luminous body driving portion configured to drive to turn on each ofthe plurality of luminous bodies;

a plurality of light leading members configured to optically separatelylead and project light beams exiting from the plurality of luminousbodies which are turned on by the luminous body driving portion;

a movable portion configured to enable relative movement of theplurality of light leading members and the luminous bodies;

a light selection control portion configured to control at least one ofthe movable portion and the luminous body driving portion in such amanner that light beams which enter the plurality of light leadingmembers are selected from light beams of the plurality of luminousbodies;

a light modulation element configured to perform light modulation withrespect to light beam entered thereto in accordance with image data;

an illumination member configured to illuminate the light modulationelement with light beams exiting from the plurality of light leadingmembers; and

a display control portion configured to control the light selectioncontrol portion and the light modulation element in such a manner thatthe light modulation element suitable for light beams exiting from theplurality of light leading members is illuminated with the exiting lightbeams.

According to a second aspect of the present invention, there is provideda projection display apparatus comprising:

a plurality of luminous bodies;

lighting means for driving to turn on each of the plurality of luminousbodies;

a plurality of light leading means for optically separately leading andprojecting light beams exiting from the plurality of luminous bodieswhich are turned on by the lighting means;

movable means for enabling relative movement of the plurality of lightleading means and the luminous bodies;

light selection controlling means for controlling at least one of themovable means and the lighting means in such a manner that light beamswhich enter the plurality of light leading means are selected from lightbeams of the plurality of luminous bodies;

a light modulation element which performs light modulation with respectto light beam entered thereto in accordance with image data;

illuminating means for illuminating the light modulation element withlight beams exiting from the plurality of light leading means; and

display controlling means for controlling the light selectioncontrolling means and the light modulation element in such a manner thatthe light modulation element suitable for light beams exiting from theplurality of light leading means is illuminated with the exiting lightbeams.

Advantages of the invention will be set forth in the description whichfollows, and in part will be obvious from the description, or may belearned by practice of the invention. Advantages of the invention may berealized and obtained by means of the instrumentalities and combinationsparticularly pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention, andtogether with the general description given above and the detaileddescription of the embodiments given below, serve to explain theprinciples of the invention.

FIG. 1 is a function block diagram of an illumination unit in aprojection display apparatus according to a first embodiment of thepresent invention illustrating an illumination principle;

FIG. 2 is a view showing a configuration of a light emission unitportion;

FIG. 3 is a view showing a relationship between an applied current and alight emission quantity of an LED in a modeling graph.

FIG. 4 is a view showing light emission timings of seven LEDs depictedin FIG. 2.

FIG. 5A is a view showing another modification of the light emissionunit portion in the first embodiment as seen from a rear surface;

FIG. 5B is a cross-sectional view taken along a line BB′ depicted inFIG. 5A;

FIG. 6 is a block diagram showing the projection display apparatusaccording to the first embodiment;

FIG. 7 is a view showing a modification of the projection displayapparatus according to the first embodiment;

FIG. 8A is a cross-sectional view showing a configuration of a rodoperating type illumination unit which is used in a projection displayapparatus according to a second embodiment of the present invention;

FIG. 8B is a right-hand side view of the rod operating type illuminationunit which is used in the projection display apparatus according to thesecond embodiment;

FIG. 9 is a view showing a relationship between an arrangement of LEDsand light leading rod members in a projection display apparatusaccording to a third embodiment of the present invention;

FIG. 10 is a view showing an optical configuration of the projectiondisplay apparatus according to the third embodiment;

FIG. 11 is a view showing a relationship between positions of the lightleading rod members and driving timings of light modulation elements;

FIG. 12 is a block diagram of an electrical control system of theprojection display apparatus according to the third embodiment;

FIG. 13 is a view showing an optical configuration of a projectiondisplay apparatus according to a fourth embodiment of the presentinvention;

FIG. 14 is a view showing driving timings of rod operating typeillumination units and optical modulation elements;

FIG. 15 is a block diagram showing an electrical control system of theprojection display apparatus according to the fourth embodiment;

FIG. 16 is a view showing an optical configuration of a projectiondisplay apparatus according to a fifth embodiment of the presentinvention;

FIG. 17 is a view showing another example of the optical configurationof the projection display apparatus according to the fifth embodiment;

FIG. 18 is a view showing still another example of the opticalconfiguration of the projection display apparatus according to the fifthembodiment;

FIG. 19 is a block diagram showing an electrical control system of theprojection display apparatus according to the fifth embodiment;

FIG. 20 is a view showing timings of light emission of LEDs and drivingof light modulation elements;

FIG. 21 is a view showing an optical configuration of a projectiondisplay apparatus according to a sixth embodiment of the presentinvention;

FIG. 22 is a view showing driving timings of rod operating typeillumination units and light modulation elements;

FIG. 23A is a view showing spectral characteristics of a DM “1” depictedin FIG. 21;

FIG. 23B is a view showing spectral characteristics of a DM “2” depictedin FIG. 21;

FIG. 24 is a view showing an optical configuration of a modification ofthe projection display apparatus according to the sixth embodiment;

FIG. 25 is a view showing an optical configuration of a projectiondisplay apparatus according to a seventh embodiment of the presentinvention;

FIG. 26 is a view showing driving timings of rod operating typeillumination units and light modulation elements;

FIG. 27 is a view showing spectral characteristics of a DM depicted inFIG. 25;

FIG. 28 is a chromaticity diagram showing a chromaticity coordinate ofan LED of each color used in each rod operating type illumination unit,a color coordinate combined for each color and an area of a color whichcan be reproduced;

FIG. 29 is a view showing a configuration of an image signal processingcircuit for color information conversion;

FIG. 30 is a view showing an optical configuration of a projectiondisplay apparatus according to an eighth embodiment of the presentinvention;

FIG. 31 is a view showing an optical configuration of a modification ofthe projection display apparatus according to the eighth embodiment;

FIG. 32 is a block diagram showing an electrical control system of theprojection display apparatus according to the eighth embodiment;

FIG. 33 is a view showing driving timings of respective rod operatingtype illumination units;

FIG. 34 is a view showing an optical configuration of a projectiondisplay apparatus according to a ninth embodiment of the presentinvention;

FIG. 35 is a chromaticity diagram showing a chromaticity coordinate ofan LED of each color used in each rod operating type illumination unitand an area of a color which can be reproduced when the configuration ofthe projection display apparatus according to the ninth embodiment isutilized and the number of G-based colors is two;

FIG. 36 is a chromaticity diagram showing a chromaticity coordinate ofan LED of each color used in each rod operating type illumination unitand an area of a color which can be reproduced when the configuration ofthe projection display apparatus according to the ninth embodiment isutilized and the number of R-based colors is two;

FIG. 37 is a view showing a relationship between an arrangement of LEDsand light leading rod members in a rod operating type illumination unitwhich is used in a projection display apparatus according to a tenthembodiment of the present invention;

FIG. 38 is a view showing an optical configuration of a projectiondisplay apparatus according to an eleventh embodiment of the presentinvention;

FIG. 39A is a view showing a relationship between an arrangement of LEDsand light leading rod members in a rod operating type illumination unitused in the projection display apparatus according to the eleventhembodiment;

FIG. 39B is a cross-sectional view taken along a line BB′ depicted inFIG. 39A;

FIG. 39C is a view schematically showing a shape of an exiting lightflux taken along a line CC′ depicted in FIG. 39B; and

FIG. 39D is a view schematically showing an exiting light flux takenalong a line DD′ depicted in FIG. 39B.

DETAILED DESCRIPTION OF THE INVENTION

[First Embodiment]

Prior to explaining a first embodiment of a projection display apparatusaccording to the present invention in detail, a basic illuminationprinciple of an illumination unit in a projection display apparatusaccording to the first embodiment of the present invention will first bedescribed.

Here, explaining the illumination principle with reference to FIGS. 1and 2, an illumination target area is brightly illuminated by using: aluminous body driving portion 7 as lighting portions corresponding tolighting means, having a function which adjusts a light emissionquantity of luminous bodies, e.g., high-luminance LEDs; optical lenses17 and 18 as an illumination portion corresponding to illuminatingmeans, which condense light of a lighted luminous body on theillumination target area; a luminous body movable portion 4 as a movableportion corresponding to movable means, e.g., a voice coil motor 12which causes a support member 11 as a light control member to beoperable; and a light selection control portion corresponding to lightselection controlling means comprising a luminous body movable controlportion 2 which gives a control quantity for moving an LED to a lightemission reference position corresponding to the center of a lightcondensing area of the optical lenses by the movable means and aluminous body selection portion 6 which gives a control quantity to thelighting means so that an LED placed at the luminous body referenceposition emits light by supplying a single-pulse-like large current tothe LED.

An operation start command portion 1 outputs a signal which commandsstart of an illumination operation by the illumination unit. The outputof this operation start command can be engaged with a non-illustratedtrigger switch which is operated by a user in order to startillumination. Alternatively, it may be engaged with any othernon-illustrated function block which must activate the illuminationoperation. A signal output from the operation start command portion 1 isinput to the luminous body movable control portion 2.

In contrast, a plurality of luminous bodies, e.g., LEDs L1, L2, . . . ,Ln are arranged in the light emission unit portion 3. These LEDsthemselves are mechanisms capable of mechanically moving. The luminousbody movable portion 4 is configured in order to drive and move theLEDs. The luminous body movable control portion 2 gives a movementcontrol quantity of each LED to this luminous body movable portion 4.Each LED spatially moves at a high speed by the luminous body movableportion 4 in accordance with the supplied control quantity. As theluminous body movable portion 4, one which can electrically controlmovement, e.g., an electromagnetic motor, an electrostatic motor or thelike is realistic, and selecting appropriate means in accordance withdemanded conditions can suffice.

Further, a luminous body position detection portion 5 which constitutesa luminous body position detection sensor which grasps a movementquantity or a movement timing of each LED is additionally provided inthe vicinity of the LEDs. This luminous body position detection portion5 detects an LED which should be caused to emit light by detecting aposition of each LED, and outputs a signal corresponding to the detectedLED.

A signal output from the luminous body position detection portion 5 isinput to the luminous body selection control portion 6. This luminousbody selection control portion 6 selects an LED which should emit lightbased on the input signal. Then, it outputs a control quantity whichturns on/off a light emission operation or gives a light emissionquantity to the selected LED. The output control quantity is input to aluminous body driving portion selected from luminous body drivingportions 71, 72, . . . , 7 n as lighting means respectively associatedwith the LEDs L1, L2, . . . , Ln (in this example, n LEDs are provided).

It should be noted that, in regard to a distribution of luminous colors,when the LEDs L1, L2, . . . , Ln can be constituted of LEDs which canemit light having different colors, the visual persistence phenomenoncan be used to produce an illumination light in which luminous colors ofthese LEDs are mixed by setting a speed of movement of the LEDs L1, L2,. . . , Ln by the luminous body movable portion 4 to, e.g., a 1/60second or below. This perceptible mixed color can be flexibly set bycombinations of luminous colors of the respective LEDs or each lightemission quantity of the same. Therefore, when a mixed color of anillumination light which is obtained in the illumination colorcharacteristic setting portion 8 is set and information of the set mixedcolor is supplied to the luminous body selection control portion 6, theluminous body selection control portion 6 can output a control quantitycorresponding to this supplied information. As to how to set anillumination color in the illumination color characteristic settingportion 8, it is possible to adopt any one of mechanical means,electrical means, and software means. Furthermore, a content of thesetting may be of a direct type such as an illumination color to beobtained or may be of an indirect type such as setting a light emissionquantity with respect to the LEDs having different luminous colors. Itis to be noted that, as the method of setting a mixed color, a methodwhich controls and changes a light emission time of each LED may be usedbesides the method which sets a luminous color or a light emissionquantity.

That is, according to this embodiment, a plurality of LEDs areconfigured, these LEDs move at a high speed, LEDs placed at specificpositions are caused to emit light like a single pulse, and concatenateddifferent LEDs are continuously caused to emit light at specificpositions, thereby obtaining continuous light emission which isapparently equivalent to one LED.

FIG. 2 is a view showing a configuration of an illumination unit whenthe illumination unit is configured in the simplest manner by using thelight emission unit portion 3 described in connection with FIG. 1 basedon the illumination principle.

In this example, seven LEDs are used as luminous bodies. That is, theLEDs L1 to L7 are mounted on a support member 11 at equal intervals asshown in the drawing. In this example, each LED has a turret-shapedlens. The support member 11 has a mechanism capable of sliding at highspeed in a direction indicated by an arrow A1 in the drawing by a voicecoil motor 12 corresponding to the luminous body movable portion 4.

Moreover, seven reflection portions 13 are separately formed on a rearsurface of the support member 11 in such a manner that each reflectionportion 13 forms a pair with each of the LEDs L1 to L7. These reflectionportions 13 as well as a light emission element 14 and a light receptionelement 15 constitute the luminous body position detection portion 5.That is, these reflection portions 13 reflect light emitted in apredetermined direction from the light emission element 14, and fixedlyarranged to be capable of receiving light by using the light receptionelement 15. Additionally, when the reflection portion 13 arrives apredetermined light emission reference position 16 as shown in thedrawing, a reflected light is input from this position to the lightreception element 15. Therefore, it is possible to detect whether an LEDwhich forms a pair with the reflection portion exists at the lightemission reference position by counting the number of times ofreflection from the reflection portion on the initial stage. It is to benoted that the light emission reference position 16 is determined as aposition where the LED L1 is placed in the illustrated state.

An optical lens 17 which condenses an emitted light and an optical lens18 which controls an optical path so that the light condensed by theoptical lens 17 can be applied to a desired irradiation target area areconstituted on a light emission front surface of an LED placed at thelight emission reference position 16. That is, when the support member11 moves and an LED passes the light emission reference position 16, thepassing LED alone emits light and the irradiation target area isirradiated with the emitted light. When this operation is sequentiallyrepeated with respect to the LEDs L1 to L7, it is possible to obtain anillumination light in which light beams emitted from the LEDs L1 to L7are apparently substantially continuous in a given time although in atime sharing manner.

As shown in FIG. 3, a quantity of light emitted from the LED can also beincreased by increasing an applied current although there is apredetermined allowable limit. The allowable limit is of course affectedand determined by characteristics of a material used, a compositiondefect, heat radiation performances, electric conduction characteristicsof peripheral electrodes and others. However, by particularly increasingheat radiation performances in the same LED, a current which is equal toor higher than a rated applied current in continuous light emission canbe supplied, thereby obtaining a large light quantity.

In order to increase heat radiation properties, a method of radiatingheat in a shorter time by enhancing heat conduction properties aroundthe LEDs is taken for granted, and light emission with heat generationbeing suppressed is enabled by assuring a long non-light-emission timeby pulse light emission in a very short time rather than continuouslight emission. That is, observing in a light emission time only, lightemission can be performed while increasing the brightness to be higherthan that in continuous light emission by applying a larger quantity ofa current in a very short time. An intensive light which cannot beobtained in continuous light emission can be produced by utilizing suchcharacteristics and using the illumination principle like thisembodiment.

It is to be noted that although the LEDs L1 to L7 move with respect tothe optical lenses 17 and 18 in this above description, the opticallenses 17 and 18 may move relatively with respective to the LEDs L1 toL7, and it is needless to say that the same advantages can be obtainedeven if such a configuration is adopted.

FIG. 4 is a timing chart showing light emission timings of the LEDs L1to L7 described in connection with FIG. 2. The horizontal axisrepresents time, and the vertical axis represents the light emissionquantity. As apparent from FIG. 4, the respective LEDs L1 to L7 aresubjected to time sharing, and a light emission control is effected insuch a manner that the LEDs L1 to L7 are continuous.

It is to be noted that the optical configuration which obtains anillumination light can be likewise taken when one rod lens substitutesfor the optical lenses 17 and 18.

Further, the optical lenses 17 and 18 may be arranged at positions apartfrom the LEDs by arranging a rod member as light leading means (a lightleading member) which leads and projects light from each LED to theoptical lens 17 in front of the optical lens 17.

As shown in FIGS. 5A and 5B, still another modification of the lightemission unit portion 3 in this embodiment adopts a configuration inwhich a plane reflection mirror 21 as a light control member coupledwith a rotary shaft 20 is integrated. The rotary shaft 20 is supportedby a rotary shaft bearing 22 and coupled with a driving motor 23. Theplane reflection mirror 21 can rotate at a high speed in a directionindicated by an arrow A2 in the drawing by this driving motor 23.

In contrast, a drum-shaped drum support member 24 is fixed and formedwith the rotary shaft 20 being used as a common central axis as shown inthe drawing, and LEDs 25 as luminous bodies form two stages and areclosely arranged along a side surface on the inner side of the drumsupport member 24. It is to be noted that different luminous colors ofthe respective LEDs 25 are represented by giving different hatchings inFIG. 5A (and hence, the hatchings do not represent a cross section), andFIG. 5B shows LED sequences 26R, 26G and 26B instead of each LED 25, inwhich the same color is continuously arranged, a circumference isdivided in accordance with each set color (indicated by a hatching of adifferent broken line) and luminous colors are switched in the order ofa red (R) color, a green (G) color and a blue (B) color in a process ofone rotation.

Furthermore, two sets of condenser lenses 27 are supported by a rotarysupport member 28 integrated with the rotary shaft 20 so that thecondenser lenses 27 can rotate and move in cooperation with the planereflection mirror 21. It is to be noted that the number of stages onwhich the LEDs 25 are arranged is basically the same as the number ofsets of the condenser lenses 27, but the number is not restrictedthereto, and setting an appropriate number according to needs cansuffice.

In such a configuration, an illumination light which can generate fieldimages of three primary colors which are required for a color image ofone frame can be obtained with respect to one rotation of the planereflection mirror 21. That is, the LEDs 25 arranged on the drum supportmember 24 sequentially repeat light emission in a time sharing manner,and perform chain light emission in such a manner that the LEDs goaround on the side surface on the inner periphery (light emission points29 go around). In this case, when the plane reflection mirror 21performs a rotation operation, light emission control is effected insuch a manner that LEDs 25 which have a correspondence relationship withthe plane reflection mirror 21 emit light in synchronization with thisrotation operation. That is, there is formed a configurationrelationship in which light beams emitted from the LEDs 25 are reflectedand condensed by the plane reflection mirror 21, and then projected toan irradiation target area through the optical lens 30.

That is, when the plane reflection mirror 21 performs the rotationoperation, there is carried out a light emission control in such amanner that the LEDs 25 which have a correspondence relationship withthe plane reflection mirror 21 emit light in synchronization with thisrotation operation. However, the condenser lens 27 is provided in anarrangement relationship with which light from the light emitting LEDs25 can be excellently acquired. That is, there is formed a configurationrelationship in which light beams from the light emitting LEDs 25 areonce condensed by the condenser lens 27, and the condensed light isreflected by the plane reflection mirror 21 so that its optical path isinflected and projected to an irradiation target area through theoptical lens 30.

As the first embodiment of the present invention, the description hasbeen given on the basic principle that the plurality of LEDs L1 to Ln or25 are constituted, these LEDs move at a high speed or the planereflection mirror 21 and the condenser lens 27 rotate and move at a highspeed, the LEDs placed at specific positions (the light emissionreference position 16 or the light emission points 29) are caused toemit light like single pulses and the linked different LEDs arecontinuously caused to emit light, thereby obtaining continuous lightemission which is apparently equivalent to one LED.

In particular, although the description has been given as to theillumination unit which brightly illuminates an irradiation target areawith a condensed light or a parallel light, such an illumination unitcan be also utilized for so-called flash illumination which isillumination of an imaging apparatus. Moreover, the description has beengiven on the example of illumination in a predetermined short time inorder to simplify the explanation in this embodiment, but the presentinvention is not restricted thereto, and it can be also applied to anillumination unit such as a torch light which performs continuousillumination.

A projection display apparatus according to the first embodiment of thepresent invention comprises one illumination unit 100, and one lightmodulation element 200 which performs light modulation with respect tolight from the illumination unit 100 in accordance with image data.

The illumination unit 100 has: a plurality of luminous bodies 101 suchas LEDs; a luminous body driving portion 102 as a lighting portioncorresponding to lighting means which drives to turn on each of theplurality of luminous bodies 101; light leading members 103corresponding to a plurality of light leading means which separatelyoptically lead and project light exiting from the plurality of luminousbodies 101 which are turned on by the luminous body driving means 102; amovable portion 104 corresponding to movable means which enablesrelative movement of the plurality of light leading members 103 and theluminous bodies 101; a sensor 105 which detects a relative movementquantity or a positional relationship of the plurality of light leadingmembers 103 and the luminous bodies 101 realized by the movable portion104; a movable means driving portion 106 which drives the movableportion 104 in such a manner that light which enters the plurality oflight leading members 103 is selected from light from the plurality ofluminous bodies 101; and/or a light selection control portion 107corresponding to light selection controlling means which controls theluminous body driving portion 102.

It is to be noted that the luminous bodies 101 in this examplecorrespond to the luminous bodies L1 to L7 and the LEDs 25. The luminousbody driving portion 102 corresponds to the luminous body drivingportions 71 to 7 n. The light leading member 103 corresponds to theplane reflection mirror 21. Additionally, as this light leading member103, it is possible to utilize a solid glass rod member, a hollow lightpipe whose inner surface is a light reflection film, or the like inaccordance with an actual mechanical configuration of the illuminationunit 100. The movable portion 104 corresponds to the luminous bodymovable portion 4, the voice coil motor 12 or the driving motor 23. Thesensor 105 corresponds to the luminous body position detection portion 5or the light emission element 14 and the light reception element 15. Thelight selection control portion 107 corresponds to the light selectioncontrolling means comprising the luminous body control portion 2 and theluminous body selection control portion 6.

Further, the light modulation element 200 is a transmission type LCD ora reflection type LCD or a two-dimensional micromirror deflection arraywhich is known as a trademark DMD (a digital micromirror device). Sincethe DMD is disclosed in, e.g., U.S. Pat. No. 6,129,437, its detailedexplanation will be eliminated.

The projection display apparatus according to this embodiment furthercomprises an illumination member 300 corresponding to illuminatingmeans, a projection optical system 400, an operation panel 500, adisplay control portion 600 corresponding to display controlling means,and a light modulation element driving portion 201.

In this example, the illumination member 300 evenly illuminates thepredetermined light modulation element 200 with light exiting from theplurality of light leading members 103, and corresponds to the opticallenses 17, 18 and 30. Furthermore, this may have a configuration whichdivides or combines a light flux by using a dichroic mirror (which willbe referred to as a DM hereinafter) or combines light fluxes by using apolarizing beam splitter (which will be referred to as a PBShereinafter) in accordance with actual mechanical structure andarrangement of each portion in the projection display apparatus.

Moreover, the projection optical system 400 performs expansion andprojection of an image of the light modulation element 200. That is, bydisplaying an image in the light modulation element 200, e.g., atransmission type LCD, the displayed image can be expanded and projectedon a screen 700 by using the projection optical system 400. Thisprojection optical system 400 may be an optical lens only or an opticalsystem including a device which combines light fluxes by using a DM inaccordance with actual mechanical structure and arrangement of eachportion in the projection display apparatus.

The operation panel 500 is a panel on which operation buttons and othersare arranged which instruct start/end of operations for projection anddisplay with respect to the display control portion 600.

The display control portion 600 performs data conversion (colorinformation and a display rate) of an input video signal in response toan operation start command from the operation panel 500. Additionally,it controls driving timings of the light selection control portion 107and the light modulation element driving portion 201 which drives thelight modulation element 200 in accordance with resulting image data insuch a manner a color light which can be appropriately controlled by thelight modulation element 200 can be applied.

It is to be noted that projection and display of a color video areenabled by using a plurality of types (e.g., three types R, G and B) ofluminous bodies which emit different luminous colors as the luminousbodies 101 and driving the light modulation element 200 based on imagedata having colors according to the types of the luminous bodies 101which emit light. That is, in this case, the display control portion 600controls the light selection control portion 107 in such a manner thatlight beams having different colors exit from the illumination unit 100in time series, and drives the light modulation element 200 by using thelight modulation element driving portion 201 at a rate which isseveral-fold of a frame rate of an input color video signal, therebyprojecting and displaying each color in one frame in a time sharingmanner.

According to the projection display apparatus having such aconfiguration, by causing each luminous body 101 to instantaneously emitan intensive light for a predetermined period, it is possible to obtaina large quantity of light while reducing a load of each luminous body101 itself which suppresses heat generation itself and has excellentheat radiation properties, and obtain an apparently continuous verybright illumination light by sequential execution of the operation ofthe different luminous bodies 101 in a chain manner by moving theluminous bodies 101 themselves or light leading areas of the lightleading members 103 at a high speed. That is, it is possible toconstitute the projection display apparatus using the illumination unit100 which is effectively intended to efficiently produce a light fluxhaving the high light condensing properties or parallelism which cannotbe realized by a method which simply arranges many luminous bodies 101such as LEDs and brings in a light quantity by simultaneously lightingthe luminous bodies 101.

Further, a color projection display apparatus having a wide colorreproduction area is configured by using a plurality of types ofluminous bodies 101 which emit different luminous colors.

A modification of the projection display apparatus according to thefirst embodiment has, as shown in FIG. 7, individual illumination units101 for each of R, G and B. That is, this modification comprises threeillumination units 100 and three light modulation elements 200R, 200Gand 200B. Even though one light leading member is included in eachillumination unit 100, the entire projection display apparatus has aplurality of light leading members 103R, 103G and 103B.

In this modification, an illumination unit 100 having the configurationdepicted in FIG. 6, an illumination member 300, a light modulationelement 200 and a light modulation element driving portion 201 areprovided in accordance with each color as indicated by giving R, G and Bto reference numerals of the respective portions, and this modificationis the same as the projection display apparatus according to the firstembodiment shown in FIG. 6 except that these constituent parts arecontrolled in accordance with image data of each color (data R, data Gand data B) obtained when a display control portion 600 processes aninput color video signal, thereby eliminating the explanation of thismodification.

In this case, however, the three light modulation elements 200R, 200Gand 200B can perform expansion and projection of images on a screen 700in one projection optical system 400 by arranging a DM 401 between eachlight modulation element 200 (which is shown as an LCD in FIG. 7) andthe projection optical system 400.

It is to be noted that the plurality of luminous bodies 101 and lightleading members 103 may be of course provided in one illumination unit100. In such a case, such a timing control as shown in FIG. 4 isexecuted with respect to the plurality of luminous bodies 101 in eachillumination unit 100.

[Second Embodiment]

A second embodiment according to the present invention will now bedescribed. As shown in FIGS. 8A and 8B, a rod operating typeillumination unit 800 used in the projection display apparatus accordingto this second embodiment has a plurality of luminous bodies and lightleading members corresponding to light leading means integrallyconfigured, and comprises a plurality of illumination units each ofwhich outputs light exiting therefrom in a predetermined direction.

That is, in this rod operating type illumination unit 800, two polygonallight leading rod members 802 constituted of L-shaped optical surfacesattached to a rod holder 801 as a holding tool capable of swiveling arerotated by a motor 803 as a movable portion corresponding to movablemeans. Further, one or two of LEDs 805 as a plurality of luminous bodiesarranged on an inner periphery of an LED substrate 804 formed into adrum-like shape are sequentially turned on with respect to each lightleading rod member 802 in accordance with rotation of the light leadingrod members 802. It is to be noted that the light leading rod member 802has a polygonal shape because the LED 805 has a rectangular shape andhence the efficiency can be increased if the shape of the light leadingrod member 802 is close to the rectangular shape and losses generatedwhen bending into an L shape can be suppressed to the minimum level.Furthermore, the L-shaped light leading rod member 802 may bemanufactured by integral molding, or it may be formed by boding threecomponents, i.e., a prismatic parallel rod 802 a, a reflection prism 802b which has a reflection coat applied thereon and used for optical pathinflection and a tapered rod 802 c.

Moreover, a projection end surface 802 d of the light leading rod member802 is determined as a virtual light source, and a Koehler illuminationoptical system which forms an optical pupil on a display device 202 as alight modulation element by a superimposition lens 301 as anillumination member corresponding to illuminating means is constituted.

The motor 803 is driven by a motor driving circuit 806 as a movableportion driving portion, and each LED 805 is driven by an LED drivingcircuit 807 as a luminous body driving portion. The motor drivingcircuit 806 and the LED driving circuit 807 are controlled by a lightemission control circuit 808 as a light selection control portioncorresponding to light selection controlling means. In this case, thelight emission control circuit 808 controls a light emission timing ofeach LED 805 based on rotation position detection of the rod holder 801by a rotation sensor 809.

By sequentially switching the plurality of LEDs 805 for pulse lightemission and selecting and changing a relative position relationshipwith the light leading rod members 802 which fetch radiated light inaccordance with light emission switching of the LEDs 805, the LEDs whichhas an effectively high luminance can be obtained, and light having alarge light quantity and an improved parallelism can be obtained fromthe light leading rod members 802.

It is to be noted that a relative position of each LED 805 and eachlight leading rod member 802 is changed by rotating the light leadingrod members 802 in this configuration, but this change in relativeposition can be also realized by moving the LEDs 805. However, movingthe light leading rod member 802 is more preferable because of thereliability in view of supply of a power to the LEDs 805. In this case,since unevenness in a light intensity distribution in, e.g., aprojection end surface 802D of the light leading rod member 802 is smallwhen the light leading rod member 802 has a length to some extent, thisprojection end surface 802 d can be regarded as a virtual rectangularsurface light source with the high evenness. Therefore, the criticalillumination may be performed with a conjugate relationship achievedbetween the display device 202 as an irradiation target and theprojection end surface 802 d of the light leading rod member 802.However, in such critical illumination, if the plurality of lightleading rod members 802 is provided like this configuration, a rimportion of the projection end surface 802 d of each light leading member802 is projected and illuminated by the irradiation target, whichresults in illumination irregularities. Since the light leading rodmembers actually rotate, an illumination area has a circular shape, andthe rim portion cannot be visually recognized depending on a rotationalspeed. However, the rim portion of the rod projection end surface 802 dhas illumination irregularities at a given moment, the illuminationirregularities change in the area every second, and the criticalillumination cannot be applied to the display device 202 which performsgradation display in a time sharing manner. On the contrary, like thisconfiguration, in case of Koehler illumination which converts an angularintensity distribution of a light flux exiting from each light leadingrod member 802 into a positional intensity distribution in anillumination area, even if each light leading rod member 802 is shifted,an angular intensity distribution of a light flux exiting from eachlight leading rod member 802 is not changed, thereby realizing anillumination unit having small illumination irregularities in anillumination area.

Therefore, since bright illumination with small illuminationirregularities is enabled by configuring the projection displayapparatus using such a rod operating type illumination unit 800, abright video without irregularities can be projected and displayed.

[Third Embodiment]

A third embodiment according to the present invention will now bedescribed. The third embodiment performs projection and display of acolor video by using a rod operating type illumination unit 800 whichprojects colored light beams which are different in time series from twolight leading rod members 802, and two light modulation elements 200.

That is, in this embodiment, in the rod operating type illumination unit800, as the plurality of LEDs 805 arranged on the inner periphery of theLED substrate 804 formed into a drum shape such as shown in FIG. 8A,LEDs having a green (G) luminous color are arranged at a partcorresponding to an approximately ½ periphery, LEDs having a red (R)luminous color are arranged at a part corresponding to an approximately¼ periphery, and LEDs having a blue (B) luminous color are arranged at apart corresponding to approximately ¼ periphery. By adopting such anarrangement of the LEDs 805, since one of the two light leading rodmembers “A” 802A and “B” 802B is placed at a position of the LEDs havingthe luminous color G even if these light leading rod members “A” 802Aand “B” 802B are rotated by a motor 803, light G always exits from therod operating type unit 800. On the contrary, light R and light B areswitched and projected every ¼ rotation of the light leading rod members“A” 802A and “B” 802B. Therefore, the two colors always exit from therod operating type unit 800.

As shown in FIG. 10, a polarizing direction of light exiting from such arod operating type illumination unit 800 is converted by a polarizationconversion element 302. This polarization conversion element 302 dividesa natural light into two polarizing directions, converts polarization insuch a manner that one polarizing direction matches with the otherpolarizing direction, thereby efficiently converting polarization intoone polarizing direction. It is to be noted that this polarizationconversion element 302 is required since an LCD is used as the lightmodulation element 200 in this embodiment, and it is not required when aDMD is used as the light modulation element 200.

Light whose polarizing direction has been converted by such apolarization conversion element 302 is caused to enter a DM “1” 304through a lens 303. As this DM “1” 304, a dichroic mirror whichtransmits light having a wavelength of light R and light B therethroughand reflects light having a wavelength of light G thereon is used. Thus,the light R and the light B transmitted through this DM “1” 304 arereflected by a mirror 305, and applied to a first light modulationelement (a transmission type LCD “1” in this embodiment) 200-1. Further,the light G reflected on the DM “1” 304 is reflected by a mirror 306,and applied to a second light modulation element (a transmission typeLCD “2” in this embodiment) 200-2.

The light beams transmitted through these light modulation elements200-1 and 200-2 enter a DM “2” 401. As this DM “2” 401, a dichroicmirror which reflects light having a wavelength of the light R and thelight B thereon and transmits light having a wavelength of the light Gtherethrough is used. Thus, the light R or the light B from the firstlight modulation element 200-1 is combined with the light G from thesecond light modulation element 200-2 by this DM “2” 401, and thecombined light is led to a projection lens 402.

A relationship between a position of each light leading rod member and adriving timing of each light modulation element is as shown in FIG. 11.In this example, one frame means one screen display period of an inputvideo signal, and one frame is composed of two fields. The first lightmodulation element (the transmission type LCD “1”) 200-1 and the secondlight modulation element (the transmission type LCD “2”) 200-2 are bothdriven at double speed, perform display of one RG image or BG image inone field, and can effect RGB color display in one frame. In this case,as to G, the same data is displayed twice.

A configuration of an electrical control system of the projectiondisplay apparatus according to the third embodiment is as shown in FIG.12. That is, the projection display apparatus according to thisembodiment comprises an image signal processing circuit 601 and asynchronization control circuit 602 as a display control portioncorresponding to display controlling means. In this example, the imagesignal processing circuit 601 performs data conversion (colorinformation and a display rate) of an input video signal. Thesynchronization control circuit 602 displays image data of a result ofthis conversion in the light modulation elements 200-1 and 200-2 withsuch timings as shown in FIG. 11. In addition to this, thesynchronization control circuit 602 supplies a synchronization signal toa light emission control circuit 808 so that the rod operating typeillumination unit 800 operates with this display timings as shown inFIG. 11.

As described above, the color projection display apparatus compatiblewith the RGB color video signal can be constituted.

[Fourth Embodiment]

A fourth embodiment according to the present invention will now bedescribed. As shown in FIG. 13, a projection display apparatus accordingto the fourth embodiment has two rod operating type illumination units(a rod operating type illumination unit “1” 800-1 and a rod operatingtype illumination unit “2” 800-2). In this example, the rod operatingtype illumination units 800-1 and 800-2 are configured to project lightR, light G and light B in time series in one frame as shown in FIG. 14.

Furthermore, polarizing directions of the light R, light G and light Bexiting from the first rod operating type illumination unit (the rodoperating type illumination unit “1”) 800-1 are equalized in a directionP by a polarization conversion element 307, whilst polarizing directionsof the light R, light G and light B exiting from the second rodoperating type illumination unit (the rod operating type illuminationunit “2”) 800-2 are equalized in a direction S by a polarizationconversion element 308, and the respective light beams enter a PBS 309.As this PBS 309, a polarizing beam splitter which transmits light havingthe direction P as a polarizing direction therethrough and reflectslight having the direction S as a polarizing direction is adopted. Thus,the PBS 309 combines the light beams from the two rod operating typeillumination units 800-1 and 800-2.

Moreover, the light modulation element (the DMD in this embodiment) 200is irradiated with this combined light through a lens 303, and the lightmodulated by this light modulation element 200 is led to a projectionlens 402. It is to be noted that, when an LCD is used as the lightmodulation element 200, a polarization conversion element must befurther arranged between the PBS 309 and the lens 3023 in order toconvert polarization of the combined light.

With such a configuration, a light quantity of the light with which thelight modulation element 200 is irradiated is increased, therebyenabling brighter projection display.

Incidentally, in this case, as shown in FIG. 14, field sequential colordisplay is carried out by matching rotational speeds and phases of thetwo light leading rod members and further synchronizing image data sothat the two rod operating type illumination units 800-1 and 800-2 emitlight having the same color. In order to realize this, in regard to animage signal processing circuit 601 and a synchronization controlcircuit 602 shown in FIG. 15, the image signal processing circuit 601 isprovided with a function which converts an input color video signal intoa field sequential color video signal and the synchronization controlcircuit 602 is provided with a function which matches phases of the tworod operating type illumination units 800-1 and 800-2 in addition to thefunctions of the third embodiment.

It is to be noted that FIG. 15 does not show a configuration of thesecond rod operating illumination unit (the rod operating typeillumination unit “2”) 800-2, and the illustration of this configurationis eliminated because this configuration is the same as that of thefirst rod operating type illumination unit (the rod operating typeillumination unit “1”) 800-1 (this is also applied to a block diagram ofan electrical control system used in the explanation of each of thefollowing embodiments).

[Fifth Embodiment]

A description will now be given as to a projection display apparatusaccording to a fifth embodiment of the present invention which comprisestwo rod operating type illumination units and two light modulationelements.

FIGS. 16 to 18 are views showing an optical configuration of theprojection display apparatus according to the fifth embodiment.Additionally, FIG. 19 is a block diagram of an electrical control systemof the projection display apparatus according to this embodiment, andFIG. 20 shows a timing chart of light emission of LEDs and driving oflight modulation elements.

That is, in the configuration shown in FIG. 16, the first rod operatingtype illumination unit (the rod operating type illumination unit “1”)800-1 is configured to always emit light G as shown in FIG. 20. A firstlight modulation element (a DMD “1”) 200-1 is irradiated with the lightG exiting from this first rod operating type illumination unit 800-1through a lens 303-1. In contrast, a second rod operating typeillumination unit (a rod operating type illumination unit “2”) 800-2 isconfigured to emit light R and light B in time series as shown in FIG.20. A second light modulation element (a DMD “2”) 200-2 is irradiatedwith light R and light B exiting from this second rod operating typeillumination unit 800-2 through a lens 303-2. Further, the light beamsmodulated by the first and second light modulation elements 200-1 and200-2 are combined by a DM 401 and led to a projection lens 402.

Furthermore, in the configuration shown in FIG. 17, light G exiting froma first rod operating illumination unit (a rod operating typeillumination unit “1”) 800-1 configured to always emit the light G islikewise applied to a first light modulation element (an LCD “1”) 200-1through a polarization conversion element 302-1 and a lens 303-1.Moreover, light R and light B exiting from a second rod operating typeillumination unit (a rod operating type illumination unit “2”) 800-2configured to emit the light R and the light B in time series arelikewise applied to a second light modulation element (an LCD “2”) 200-2through a polarization conversion element 302-2 and a lens 303-2.Moreover, the light beams modulated by the first and second lightmodulation elements 200-1 and 200-2 are combined by a DM 401 and led toa projection lens 402.

Additionally, in the configuration shown in FIG. 18, a polarizingdirection of light G exiting from a first rod operating typeillumination unit (a rod operating type illumination unit “1”) 800-1configured to always emit the light G is uniformed into a direction P bya polarization conversion element 307, then the light G enters a PBS309-1 through a lens 303-1, is transmitted through the PBS 309-1 andapplied to a first light modulation element (a reflection type LCD(which will be referred to as an LCOS hereinafter) “1”) 200-1. Further,the light G which has been modulated by this first light modulationelement 200-1 and whose polarizing direction has been converted into adirection S is reflected by the PBS 309-1 and enters a DM 401.Furthermore, likewise, polarizing directions of light R and light Bexiting from a second rod operating type illumination unit (a rodoperating type illumination unit “2”) 800-2 configured to emit the lightR and the light B in time series are uniformed into a direction S by apolarization conversion element 308, then these light beams enter a PBS309-2 through a lens 303-2, are reflected by the PBS 309-2 and appliedto a second light modulation element (an LCOS “2”) 200-2. Furthermore,the light R and the light B which have been modulated by this secondlight modulation element 200-2 and whose polarizing directions have beenconverted into a direction P are transmitted through the PBS 309-2, andenter the DM 401. Thus, the light beams modulated by the first andsecond light modulation elements 200-1 and 200-2 are combined by the DM401 and led to a projection lens 402.

In the configurations shown in FIGS. 16 to 18, the second rod operatingtype illumination unit 800-2 which performs time-series illumination ofthe light R and the light B must be synchronized with image data. On thecontrary, although it is preferable that the first rod operating typeillumination unit 800-2 for the light G is synchronized with image data,but it may not be synchronized with it. Moreover, the light modulationelements 200-1 and 200-2 are both driven at a double speed, but matchingdriving times improves the efficiency of the circuits.

It is to be noted that each of the first and second rod operating typeillumination units 800-1 and 800-2 comprises a motor 803 in theconfiguration shown in FIG. 19, but each unit may not comprise thismotor. In this case, it is sufficient to provide an interlockingmechanism such as a belt drive which rotates the both light leading rodmembers to one motor, for example.

Additionally, although the LEDs for G which is a color whose lightemission quantity should be aboundingly utilized are always turned ontaking the color balance into consideration so that a combined light inone frame period has a desired white color, LEDs for R or B may bealways turned on depending on characteristics of LEDs used in somecases.

[Sixth Embodiment]

A projection display apparatus according to a sixth embodiment of thepresent invention will now be described. This embodiment obtainsbrighter illumination by simultaneously illuminating one lightmodulation element by two illumination units driven by luminous bodieshaving slightly different wavelengths.

That is, in the projection display apparatus according to thisembodiment, as shown in FIG. 21, a first rod operating type illuminationunit (a rod operating type illumination unit “1”) 800-1 is configured toalways emit a green (G1) light having a wavelength of, e.g., 555 nm asshown in FIG. 22. The light G1 exiting from this first rod operatingtype illumination unit 800-1 enters a DM “1” 304. Further, a second rodoperating type illumination unit (a rod operating type illumination unit“2”) 800-2 is configured to always emit a green (G2) light having awavelength of, e.g., 520 nm as shown in FIG. 22. The light G2 exitingfrom this second rod operating type illumination unit 800-2 also entersthe DM “1” 304.

In this example, spectral characteristics of the DM “1” 304 performreflection/transmission with a wavelength of approximately 530 nm on theboundary as shown in FIG. 23A. Thus, the light G1 with the wavelength of555 nm exiting from the first rod operating type illumination unit 800-1is transmitted, and the light G2 with the wavelength of 520 nm exitingfrom the second rod operating type illumination unit 800-2 is reflected,thereby combining the both exiting light. Furthermore, as shown in FIG.22, a first light modulation element (a DMD “1”) 200-1 is irradiatedwith the combined light G (G1+G2) through a lens 303-1.

Moreover, a third rod operating type illumination unit (a rod operatingtype illumination unit “3”) 800-3 is configured to emit light R andlight B in time series as shown in FIG. 22. The light R and the light Bexiting from the third rod operating type illumination unit 800-3 areapplied to a second light modulation element (a DMD “2”) 200-2 through alens 303-2 as shown in FIG. 22.

Additionally, the light modulated by the first and second lightmodulation elements 200-1 and 200-2 enter a DM “2” 401. Spectralcharacteristics of this DM “2” 401 reflect light having a wavelength ofapproximately 500 nm to approximately 590 nm, i.e., light in an area Gas shown in FIG. 23B. Thus, the modulated light G from the first lightmodulation element 200-1 is reflected, and the modulated light R and Bfrom the second light modulation element 200-1 are transmitted, therebycombining these light. The combined light is led to a projection lens402.

In this case, like the foregoing embodiments, the three rod operatingtype illumination units 800-1, 800-2 an 800-3 and the two lightmodulation units 200-1 and 200-2 are of course synchronously driven by asynchronization control circuit.

It is to be noted that the present invention is not restricted to theexample where one color alone is used in the two illumination units asdescribed above, and a light quantity can be increased by using twocolors or three colors in the two illumination units.

For example, an optical configuration of a projection display apparatuswhen three colors are used in the two illumination units is as shown inFIG. 24.

[Seventh Embodiment]

A projection display apparatus according to a seventh embodimentaccording to the present invention will now be described. That is, asshown in FIG. 25, the projection display apparatus according to thisembodiment has two rod operating type illumination units (a rodoperating type illumination unit “1” 800-1 and a rod operating typeillumination unit “2” 800-2). In this example, each of the rod operatingtype illumination units 800-1 and 800-2 is configured to emit light R,light G and light B in time series in one frame as shown in FIG. 26. Inthis case, wavelengths of R, G and B are different from each other. Thatis, a wavelength of the light R (R1) of the first rod operating typeillumination unit 800-1 is 610 nm, a wavelength of the light G (G1) ofthe same is 520 nm, and a wavelength of the light B (B1) of the same is470 nm. Furthermore, a wavelength of the light R (R2) of the second rodoperating type illumination unit 800-2 is 645 nm, a wavelength of thelight G (G2) of the same is 555 nm, and a wavelength of the light B (B2)of the same is 450 nm.

Moreover, the light R, light G and light B exiting from these first andsecond rod operating type illumination units 800-1 and 800-2respectively enter a DM 304. In this example, as shown in FIG. 27, thespectral characteristics of the DM 304 have three reflection bandsrespectively corresponding to the wavelength of the light R, light G andlight B exiting from the second rod operating type illumination unit800-2. Thus, the DM 604 combines the light beams from the two rodoperating type illumination units 800-1 and 800-2, a light modulationelement (a DMD in this embodiment) 200 is irradiated with this combinedlight through a lens 303, and the light modulated by this lightmodulation element 200 is led to a projection lens 402. In this case,the two rod operating type illumination units 800-1 and 800-2 and thelight modulation element 200 operate in synchronization with each other.

A chromaticity coordinate of an LED of each color used in each rodoperating type illumination unit, a color coordinate combined inaccordance with each color and an area of a color which can bereproduced have such a relationship as shown in FIG. 28.

In this example, the color coordinate combined in accordance with eachcolor corresponds to each point (a point indicated by a large blackcircle) on a line segment connecting two color coordinates (pointsindicated by small black circles) of a corresponding color, and the areaof a color which can be reproduced by a color light in which threecolors are combined corresponds to an area surrounded by a broken lineconnecting these points.

When an input color video signal is an NTSC signal, it is desirable touse an LED which can reproduce a color light corresponding to pointsindicated by a square in the drawing. However, such an LED is rare, or abright LED hardly exists. Thus, in this embodiment, an adjustment iscarried out so that a desirable color can be obtained by examiningwavelengths of two types of LEDs which are used for respective colors.

Additionally, a subtle error which cannot be processed by such anadjustment for the LED to be adopted can be adjusted by converting avideo signal itself. That is, when a color of a reference light sourceis different from a color of an illumination light when forming a videosignal, a reproduced color differs. Accordingly, color information of aninput video signal is converted so that correct color reproduction canbe carried out with a color of an illumination light.

FIG. 29 is a view showing a configuration of an image signal processingcircuit 601 which performs such color information conversion. That is,this image signal processing circuit 601 comprises a luminous coloranalysis circuit 601A and an image processing circuit 601B, and theluminous color analysis circuit 601A includes a sensor 601A1, an ROM601A2 and a data analysis circuit 601A3.

Here, the sensor 601A1 monitors a current luminous color (a wavelengthor an intensity). The ROM 601A2 stores initial correction data, and aconversion table of the correction data according to a monitoring resultobtained by the sensor 601A1. That is, a luminous color of each LEDvaries with time, and also varies depending on a temperature. Therefore,the initial correction data alone is insufficient. The data analysiscircuit 601A3 converts the initial correction data stored in the ROM601A2 in accordance with a monitoring result obtained by the sensor601A1 by using the conversion table, and supplies the conversion resultto the image processing circuit 601B.

Further, the image processing circuit 601B carries out color informationconversion with respect to input color video signals (Ri, Gi and Bi) inaccordance with correction color information from the luminous coloranalysis circuit 601A, and supplies controls signals Ro, Go and Bo ofrespective colors according to the conversion result to the lightmodulation element driving portion 201. As a result, appropriate colorreproduction can be performed in a video to be projected even if anirradiation color has irregularities in accordance with each projectiondisplay apparatus.

[Eighth Embodiment]

A projection display apparatus according to an eighth embodiment of thepresent invention will now be described. The projection displayapparatus according to this embodiment arranges an illumination unitwhich applies light of a single color and a light modulation element inaccordance with each of the three colors R, G and B.

FIGS. 30 and 31 are views showing an optical configuration of theprojection display apparatus according to the eighth embodiment.Furthermore, FIG. 32 is a block diagram showing an electrical controlsystem of the projection display apparatus according to this embodiment,and FIG. 33 is a view showing driving timings of each rod operating typeillumination unit.

That is, in the configuration depicted in FIG. 30, a first rod operatingtype illumination unit (a rod operating type illumination unit “1”)800-1 is configured to always project light R as shown in FIG. 33. Afirst light modulation element (a DMD “1”) 200-1 is irradiated with thelight R exiting from this first rod operating type illumination unit800-1 through a lens 303-1. Moreover, as shown in FIG. 33, light Gexiting from a second rod operating type illumination unit (a rodoperating type illumination unit “2”) which always projects the light Gis applied to a second light modulation element (a DMD “2”) 200-2through a lens 303-2. As shown in FIG. 33, light B exiting from a thirdrod operating type illumination unit (a rod operating type illuminationunit “3”) 800-3 which always projects the light B is applied to a thirdlight modulation element (a DMD “3”) 200-3 through a lens 303-3.Additionally, the light beams modulated by the first to third lightmodulation elements 200-1 to 200-3 are combined by a DM 401, and thecombined light is led to a projection lens 402.

Additionally, in the configuration shown in FIG. 31, light R exitingfrom a first rod operating type illumination unit (a rod operating typeillumination unit “1”) 800-1 which always projects the light R isapplied to a first light modulation element (an LCD “1”) 200-1 through apolarization conversion element 302-1 and a lens 303-1. Light G exitingfrom a second rod operating type illumination unit (a rod operating typeillumination unit “2”) 800-2 which always projects the light G isapplied to a second light modulation element (an LCD “2”) 200-2 througha polarization conversion element 302-2 and a lens 303-2. Light Bexiting from a third rod operating type illumination unit (a rodoperating type illumination unit “3”) 800-3 which always projects thelight B is applied to a third light modulation element (an LCD “3”)200-3 through a polarization conversion element 302-3 and a lens 303-3.Further, the light beams modulated by the first to third lightmodulation elements 200-1 to 200-3 are combined by a DM 401, and thecombined light is led to a projection lens 402.

It is to be noted that synchronization of the three light modulationelements 200-1, 200-2 and 200-3 is required in this embodiment, the rodoperating type illumination units 800-1, 800-2 and 800-3 may not besynchronized since each of these units constantly performs irradiationof a single color. Therefore, the configuration of the synchronizationcontrol circuit 602 becomes simpler than those of the foregoingembodiments.

[Ninth Embodiment]

A projection display apparatus according to a ninth embodiment of thepresent invention will now be described. As the input color videosignal, there is a signal having four or more colors in addition to asignal having colors R, G and B.

A high-color-reproduction color projection display apparatus compatiblewith a video signal having such a signal of four colors has such anoptical configuration as shown in FIG. 34. That is, a first light in thefour colors exiting from a first rod operating type illumination unit (arod operating type illumination unit “1”) 800-1 which constantlyprojects the first light is applied to a first light modulation element(an LCD “1”) 200-1 through a polarization conversion element 302-1 and alens 303-1. A second light in the four colors exiting from a second rodtype operating illumination unit (a rod operating type illumination unit“2”) 800-2 which constantly projects the second light is applied to asecond light modulation element (an LCD “2”) 200-2 through apolarization conversion element 302-2 and a lens 303-2. Further, a thirdlight in the four colors exiting from a third rod operating typeillumination unit (a rod operating type illumination unit “3”) 800-3which constantly projects the third light is applied to a third lightmodulation element (an LCD “3”) 200-3 through a polarization conversionelement 302-3 and a lens 303-3. A fourth light in the four colorsexiting from a fourth rod operating type illumination unit (a rodoperating type illumination unit “4”) 800-4 which constantly projectsthe fourth light is applied to a fourth light modulation element (an LCD“4”) 200-4 through a polarization conversion element 302-4 and a lens303-4. Furthermore, the light beams modulated by the first to fourthlight modulation elements 200-1 to 200-4 are combined by a DM 401, andthe combined light is led to a projection lens 402.

Incidentally, according to the projection display apparatus using thefour illumination units, for example, as shown in FIG. 35, a colorreproduction area can be enlarged by preparing two G-based colors andforming a square area.

Alternatively, as shown in FIG. 36, an application which uses twoR-based colors and enables subtle color reproduction of the red colorcan be also considered. This application can obtain a subtle color whichcan be represented by a bit number close to 16 bits with respect to acolor signal represented by eight bits, for example. The presentinvention becomes particularly effective as a display apparatus for amedical use by enabling reproduction of a subtle color in a red colorarea in this manner.

It is also possible to easily cope with color video signals of five ormore colors by increasing the number of the illumination units.

[Tenth Embodiment]

A projection display apparatus according to a tenth embodiment of thepresent invention will now be described. This embodiment is a projectiondisplay apparatus using a rod operating type illumination unit whichsubtly changes a luminous color even in case of a monochromatic light.

That is, as shown in FIG. 37, this embodiment has three light leadingrod members 802A, 802B and 802C, and LEDs having three types of redcolors (R1, R2 and R3) whose emission wavelengths are different fromeach other are arranged. In this example, it is possible to determinethat R1 has 625 nm, R2 has 630 nm and R3 has 635 nm, for example.

When the rod operating type illumination unit is driven, light beamsexiting from three light leading rod members 802A, 802B and 802C whichrotationally move become time-series R1, R2 and R3 in the respectivelight leading rod members. Further, a combined light of the three lightleading rod members is in a state where R1, R2 and R3 of three colorsare respectively constantly on. Therefore, the combined light has aluminous color formed of a plurality of wavelengths, and a luminouscolor of a red illumination light can be subtly adjusted as differentfrom a luminous color of an LED having a single wavelength.

The luminous color of the R color of the combined light can be changedby selecting wavelengths of the respective LEDs used, and also adjustedby a scheme which controls a driving current in accordance with each LEDhaving each wavelength or a scheme which changes a ratio of the numberof R1, R2 and R3.

Furthermore, luminous colors of green and blue illumination light can belikewise adjusted.

[Eleventh Embodiment]

A projection display apparatus according to an eleventh embodiment ofthe present invention will now be described. As shown in FIG. 38, theprojection display apparatus according to this embodiment uses a rodoperating type illumination unit 800 which can divide and project lightfluxes of R, G and B, and light modulation elements 200 for respectivecolors are irradiated with the light fluxes of R, G and B exiting fromthe rod operating type illumination unit 800 as illumination light beamsby lenses 303 and mirrors 306 as different illumination optical systems.Moreover, the light beams modulated by these light modulation elements200 are combined by a DM 401, and the combined light is lead to aprojection lens 402 through a mirror 403.

With such a configuration, light fluxes of the illumination unit whichemits a plurality of colors can be divided in accordance with each colorwithout using an expensive color separation unit, and the differentlight modulation elements can be illuminated with the separated lightfluxes, thereby inexpensively constituting the projection displayapparatus with the light utilization efficiency.

It is to be noted that, as shown in FIG. 39A, the rod operating typeillumination unit 800 which can divide and project the light fluxes ofR, G and B has LEDs for R, G and B respectively collectively arranged onparts each corresponding to an approximately ⅓ circumference and threelight leading rod members (a light leading rod member “A” 802A, a lightleading rod member “B” 802B and a light leading rod member “C” 802C).Although the luminous colors of the light exiting from the threerotating light leading rod members are switched in time series, thelight fluxes from the rod operating type illumination unit exit in astate where light flux areas of R, G and B are fixed in accordance withthe arrangement of the LEDs of R, G and B.

In this case, as shown in FIG. 39B which is a cross-sectional line takenalong a line BB′ of FIG. 39A, tapered rods 802 c of the respective lightleading rod members 802A, 802B and 802C are configured to be openedtoward the outside. As a result, rough shapes of projected light fluxesseen from a line CC′ and a line DD′ are as shown in FIGS. 39C and 39D.That is, the light flux is divided as distanced from a projection endsurface 802 d of each light leading rod member.

Although the above has described the present invention based on theembodiments, the present invention is not restricted to the foregoingembodiments, and various modifications or applications can be carriedout within the scope of the present invention.

For example, although the motor as a movable portion corresponding tomovable means is included in each illumination unit in, e.g., thefourth, fifth and sixth embodiments using the plurality of illuminationunits, the light leading members of the plurality of illumination unitscan be operated by using, e.g., a gear or a belt even if the number ofthe movable portion (the motor) is one.

Moreover, even if the number of the light emission control circuit isone, control over LED driving timings of the plurality of illuminationunits and control over an operation of the motor can be executed bywire-connecting each illumination unit and a control line.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details, and representative devices shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. A projection display apparatus comprising: a first illumination unitwhich projects at least red, green and blue lights in time series; asecond illumination unit which projects lights of three similar colorshaving substantially the same wavelength bands as those of the red,green and blue lights in time series; a combination portion whichcombines a light flux projected from the first illumination unit with alight flux projected from the second illumination unit, therebygenerating one light flux; a light modulation element which modulatesthe one light flux generated by the combination portion; a projectionlens which projects the light modulated by the light modulation element;and a synchronization control portion which performs synchronizationcontrol to cause the first illumination unit and the second illuminationunit to simultaneously project similar colors; wherein the similarcolors projected from the first illumination unit and the secondillumination unit have different central wave lengths.
 2. The projectiondisplay apparatus according to claim 1, wherein at least one of thefirst illumination unit and the second illumination unit comprises aluminous body driving portion which adjusts be amount of the lights ofthe respective colors that the at least one of the first illuminationunit and the second illumination unit projects, and the luminous bodydriving portion adjusts the central wavelengths of the lights of therespective colors radiated on the light modulation element by adjustingthe amount of the lights of the respective colors projected from the atleast one of the first illumination unit and the second illuminationunit.
 3. The projection display apparatus according to claim 1, whereinat least one of the first illumination unit and the second illuminationunit comprises: a sensor which monitors at least one of wavelength andintensity of projected light; and an image processing portion whichconverts color information of a video signal for use in modulation ofthe light modulation element in accordance with a result of monitoring.